FATAL error in cron log

I noticed I stopped getting rkhunter daily reports and that my server was sending spam mail and viruses out. I think I cleaned up the virus and spam problem, but as I started looking through more logs I found.

FATAL: Could not load /lib/modules/2.6.32-042stab044.11/modules.dep: No such file or directory

This is in the /var/log/ispconfig/cron.log.

I can't find much on why this is happening. I'd appreciate any advice.